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The purpose of this paper is to explore the synthesis, preparation and investigation of micro structural, optical and mechanical studies of polyvinyl alcohol (PVA) doped with tungsten oxide (WO₃) nanocomposites films. These films were prepared by simple solvent casting method is further characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV-visible spectroscopy, universal testing machine (UTM), scanning electron microscope (SEM), energy-dispersive analysis of X-rays (EDAX) and atomic force microscope (AFM) techniques to determine the enhancement in structural, optical and mechanical properties with increase in dopant concentration.

The present paper deals with the synthesis of WO₃ nanoparticles using precipitation method and doping into PVA matrix to prepare a polymer nanocomposite film using coagulation and solvent casting method. The FTIR explores the interaction of dopants with PVA matrix. The XRD spectra investigate the variation of crystallinity. The UV/Vis-spectra reveals the information of optical energy band gap and the Urbach Energy for different doping concentrations. The mechanical properties of the nanocomposites were exposed using UTM. The phase homogeneity, film topography, chemical composition of nanocomposites is analyzed using SEM, EDAX and AFM techniques supporting the above results.

The films characterized by FTIR spectroscopy explores the irregular shift in the bands of pure and doped PVA can be understood on the basis of intra/inter molecular hydrogen bonding with the adjacent OH group of PVA backbone. The XRD result reconnoiters that the particle size and crystallinity increases whereas microstructural strain and dislocation density decreases with increase in dopant concentration. Further the drastic decrease in optical energy band gap E _g =0.94 eV for doping concentration x=15 wt% and the increase in values of Urbach Energy (E _u ) with doping concentrations were investigated by UV/Vis spectra. Also the extinction coefficient was high in the wavelength range of 250-400 nm and low in the wavelength range of 400-1,200 nm. The mechanical studies indicates that the addition of the WO₃ with weight percentage concentration x=15 percent increases the tensile strength and Young’s modulus. The phase homogeneity, the particle size of the dopants and chemical composition of nanocomposites is analyzed using SEM and EDAX. The film topography of the nanocomposites is analyzed using AFM techniques supporting the above results.

The investigation of synthesis, preparation and investigation of micro structural, optical and mechanical studies of PVA doped with WO₃ nanocomposites films as been done. The results prove that these nanocomposites having good mechanical strength with crystalline nature and also very low optical energy gap value that could find possible applications in industries.

This work aims to prepare and characterize of protective anticorrosion phosphate-doped polyaniline (PANI) nanocomposite coatings for stainless steel (SS) in chloride solution.

PANI composite coatings were electrodeposited from aqueous sulfuric acid solution containing monomer and Al₂O₃ nanoparticles using cyclic voltammetry technique. Doping by phosphate was done by aging the coated steels for different periods (1–168 h) in phosphate solution. The polymer film composite was investigated by Fourier-transform infrared spectroscopy and scanning electron microscopy techniques. Potential-time, anodic polarization and electrochemical impedance spectroscopy were used to study the protection efficiency of the coatings.

The Al₂O₃ nanoparticles were incorporated into the deposited PANI layer but they decreased the deposition of polymer. The nanoparticles and the phosphate anions enhanced the protective PANI layer for passivation and protection of SS in the chloride solution.

The replacement of counter anions by phosphate ions improved significantly the PANI and its nanocomposite as protective coating of SS in chloride solution.

The purpose of this study is use to density functional theory (DFT) to investigate the molecular adsorption by PEDOT:PSS for different doping levels. DFT calculations are performed using the SIESTA code. In addition, the non-equilibrium Green’s function method is used within the TranSIESTA code to determine the quantum transport properties of molecular nanodevices.

Density functional theory (DFT) is used to investigate the molecular adsorption by PEDOT:PSS for different doping levels. DFT calculations are performed using the SIESTA code. In addition, the non-equilibrium Green’s function method is used within the TranSIESTA code to determine the quantum transport properties of molecular nanodevices.

Simulation results show very good sensitivity of Pd-doped PEDOT:PSS to ammonia, carbon dioxide and methane, so this structure cannot be used for simultaneous exposure to these gases. Silver-doped PEDOT:PSS structure provides a favorable sensitivity to ammonia in addition to exhibiting a better selectivity. If the experiment is repeated, the sensitivity is increased for a larger concentration of the applied gas. However, the sensitivity will decrease at a higher ratio than smaller concentrations of gas.

The advantages of the proposed sensor are its low-cost implementation and simple fabrication process compared to other sensors. Moreover, the proposed sensor exhibits appropriate sensitivity and repeatability at room temperature.

The purpose of this research is to synthesize Al₂O₃-ZnO thick films, study the effect of doping and optical excitation on their sensing properties and introduce an attractive candidate for acetone detection in practice.

ZnO nanoparticles doped with Al₂O₃ were prepared by sol-gel method and characterized via X-ray diffraction and field-emission scanning electron microscopy. The sensing properties to acetone were investigated with an irradiation of UV. The sensing mechanism was also discussed with UV-Vis spectroscopy.

The doping of Al₂O₃ promoted the sensing response and stability of ZnO nanoparticles. The optimum performance was obtained by 4.96 Wt.% Al₂O₃-ZnO. The response to acetone (1,000 ppm) was significantly increased to 241.81, even just at an operating temperature of 64°C. It was also demonstrated that optical excitation with UV irradiation greatly enhanced the sensing response and the sensitivity can reach up to 305.14.

The sensor fabricated from 4.96 Wt.% Al₂O₃-ZnO exhibited excellent acetone-sensing characteristics. It is promising to be applied in low power and miniature acetone gas sensors.

In the present research, the optimum performance was obtained by 4.96 Wt.% Al₂O₃-ZnO at a low operating temperature of 64°C. The sensing properties were enhanced significantly with optical excitation, and the sensing mechanism was discussed with UV-Vis spectroscopy which has been reported rarely before.

This study aims to elucidate the reaction mechanism of electroless NiP deposits on conductive but non-catalytic Cu films on the basis of their nucleation and growth without Pd catalyst and to measure the deposition rate and activation energy of electroless NiP deposits on the non-catalytic Cu film at various deposition times (60, 120, 240 and 480 s) and temperatures (70, 80 and 90°C) at pH 4.6.

Specimens with and without Pd catalyst on Cu film were prepared as follows: the Pd catalyst was deposited on half of the Cu film using a deposition protector, and the specimen containing the Pd catalyst deposited on half of its area was immersed in electroless NiP solution. The growth of NiP on the Cu films with and without the Pd catalyst was observed.

The number of Pd nanoparticles increased with Pd activation time; the nucleation of Pd dominated over growth at 60 s. Lattice images show that the d-spacing of Ni nanoparticles doped with less than 10 at% P increased to 2.050 Å. Nucleation of NiP deposits occurred simultaneously in the specimens with and without the Pd catalyst, because electrons could be transferred via the conductive Cu. Therefore, the reaction mechanism of the electroless NiP deposited on Cu film appears to be electrochemical. The activation energies for NiP deposits (15 s Pd with catalytic Pd, 15 s Pd without catalytic Pd, 60 s Pd with catalytic Pd and 60 s Pd without catalytic Pd) on the Cu film are 65.8, 64.0, 64.3 and 58.1 kJ/mol, respectively. This demonstrates that, regardless of the volume and the presence of catalytic Pd, the activation energy of electroless NiP has a consistent value.

It is necessary to study the relationship between the volume of Pd nanoparticles and the nucleation rate of NiP at an initial stage, as there are limited data regarding the effect of Pd volume on the nucleation rate of NiP.

The reaction mechanism of the electroless NiP deposited on conductive but non-catalytic Cu film involves electrochemical reactions because the nucleation of NiP deposits occurs on conductive Cu film regardless of the presence of the Pd catalyst.

The purpose of this study is to experimentally and numerically scrutinize the heat transfer enhancement in pool boiling and condensation by changing the hydrophilicity or hydrophobicity properties of the working fluid, i.e. by use of nanofluid solution.

For specifying the effects of nanoparticle concentration on heat transfer properties, two different nanofluid solutions (h-BN/DCM and SiO₂/DCM) at three different volumetric concentrations were prepared and tested under different heat flux conditions. Boiling curves, alterations in pressure with heat flux and heat transfer coefficients for both boiling and condensation processes were obtained and viscosity measurements were performed for dichloromethane (DCM) and each working fluid was prepared. In addition, a series of numerical simulations, via computational fluid dynamics approach, was performed for specifying the evaporation–condensation phenomena and temperature and velocity distributions.

Nanoparticle addition inside the base fluid increased the thermal characteristics of the base fluid significantly. For the experimental results of h-BN/DCM nanofluid, the increment rate in heat transfer coefficient for saturation boiling, after-saturation boiling and condensation processes was found as 27.59%, 14.44% and 15%, respectively.

The novelty of this comparison study is that there is no such experimental and numerical comparison study in literature for DCM fluid, which concentrates on thermal performance enhancement and compares the effect of different kinds of nanoparticles on heat transfer characteristics for boiling–condensation processes.

The purpose of this paper is to study the effect of doping, annealing temperature and visible optical excitation on CuO-ZnO nanocomposites’ acetone sensing properties and introduce an attractive candidate for acetone detection at about room temperature.

ZnO nanoparticles doped with CuO were prepared by sol-gel method, and the structure and morphology were characterized via X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy and Brunauer-Emmett-Teller. The photoelectric responses of CuO-ZnO nanocomposites to cetone under the irradiation of visible light were investigated at about 30°C. The photoelectric response mechanism was also discussed with the model of double Schottky.

The doping of CuO enhanced performance of ZnO nanoparticles in terms of the photoelectric responses and the gas response and selectivity to acetone of ZnO nanoparticles, in addition, decreasing the operating temperature to about 30ºC. The optimum performance was obtained by 4.17% CuO-ZnO nanocomposites. Even at the operating temperature, about 30ºC, the response to 1,000 ppm acetone was significantly increased to 579.24 under the visible light irradiation.

The sensor fabricated by 4.17% CuO-ZnO nanocomposites exhibited excellent acetone-sensing characteristics at about 30ºC. It is promising to be applied in low power and miniature acetone gas sensors.

In the present research, a new nanocomposite material of CuO-ZnO was prepared by Sol-gel method. The optimum gas sensing properties to acetone were obtained by 4.17% CuO-ZnO nanocomposites at about 30ºC operating temperature when it was irradiated by visible light with the wavelength more than 420 nm.

Carbon dioxide (CO₂) has attracted special scientific interest over the last years mainly because of its relation to climate change and indoor air quality. Except for this, CO₂ can be used as an indicator of food freshness, patients’ clinical state and fire detection. Therefore, the accurate monitoring and controlling of CO₂ levels are imperative. The development of highly sensitive, selective and reliable sensors that can efficiently distinguish CO₂ in various conditions of temperature, humidity and other gases’ interference is the subject of intensive research with chemi-resistive zinc oxide (ZnO)-based sensors holding a privileged position. Several ZnO nanostructures have been used in sensing applications because of their versatile features. However, the deficient selectivity and long-term stability remain major concerns, especially when operating at room temperature. This study aims to encompass an extensive study of CO₂ chemi-resistive sensors based on ZnO, introducing the most significant advances of recent years and the best strategies for enhancing ZnO sensing properties.

An overview of the different ZnO nanostructures used for CO₂ sensing and their synthesis methods is presented, focusing on the parameters that highly affect the sensing mechanism and, thus, the performance of CO₂ sensors.

The selectivity and sensitivity of ZnO sensors can be enhanced by adjusting various parameters during their synthesis and by doping or treating ZnO with suitable materials.

This paper summarises the advances in the rapidly evolving field of CO₂ sensing by ZnO sensors and provides research directions for optimised sensors in the future.

The research on lead-free solder alloys has increased in past decades due to awareness of the environmental impact of lead contents in soldering alloys. This has led to the introduction and development of different grades of lead-free solder alloys in the global market. Tin-silver-copper is a lead-free alloy which has been acknowledged by different consortia as a good alternative to conventional tin-lead alloy. The purpose of this paper is to provide comprehensive knowledge about the tin-silver-copper series.

The approach of this study reviews the microstructure and some other properties of tin-silver-copper series after the addition of indium, titanium, iron, zinc, zirconium, bismuth, nickel, antimony, gallium, aluminium, cerium, lanthanum, yttrium, erbium, praseodymium, neodymium, ytterbium, nanoparticles of nickel, cobalt, silicon carbide, aluminium oxide, zinc oxide, titanium dioxide, cerium oxide, zirconium oxide and titanium diboride, as well as carbon nanotubes, nickel-coated carbon nanotubes, single-walled carbon nanotubes and graphene-nano-sheets.

The current paper presents a comprehensive review of the tin-silver-copper solder series with possible solutions for improving their microstructure, melting point, mechanical properties and wettability through the addition of different elements/nanoparticles and other materials.

This paper summarises the useful findings of the tin-silver-copper series comprehensively. This information will assist in future work for the design and development of novel lead-free solder alloys.

The purpose of this paper is to investigate the effects of addition Co nanoparticles on the characteristic properties of Sn‐3.8Ag‐0.7Cu solder.

Cobalt (Co) nanoparticles were added to Sn‐Ag‐Cu solders by thoroughly blending various weight percentages (0‐2.0 wt%) of Co nanoparticles with near eutectic SAC387 solder paste. Blending was done mechanically for 30 min to ensure a homogeneous mixture. The paste mixture was then reflowed on a hot plate at 250°C for 45 s. The melting points of nanocomposite solder were determined by differential scanning calorimetry. Spreading rate of nanocomposite was calculated following the JIS Z3198‐3 standard. The wetting angle was measured after cross‐sectional metallographic preparation.

No significant change in melting point of the solder was observed as a result of Co nanoparticle addition. The wetting angles of the solder increased with the addition of nanoparticles, while the spreading rate decreased. Although the wetting angle increased, the values were still within the acceptable range. Scanning micrograph observations revealed that the as‐solidified microstructure of the composite solder was altered by the addition of Co nanoparticles. Microhardness of the solders slightly increased upon Co nanoparticles addition to SAC387.

The paper demonstrates that a simple process like paste mixing can be used to incorporate nanoparticles into solder.